Generating atomistic morphologies

One essential part of our Virtual Lab is the virtual workbench for generating and analyzing thin films of organic electronic molecules. This area comprises several simulation and analysis tools: Deposit models the physical vapour deposition process (PVD) of organic small molecule thin-films, either pristine layers, mixed thin films or interfaces, such as used in OLED, OFET and OPV applications. Realistic thin-films on the 10 nm scale with atomic resolution are deposited from the ground up by adding molecules to the simulation box one at a time.

During the thermodynamic equilibration of each molecule, the interaction between and within molecules is modeled using customized forcefields. These molecule-specific forcefields are automatically derived from quantum-mechanical calculations using the Parametrizer and DihedralParametrizer module. The growth of a thin film of alpha-NPD, with the deposition of one molecule highlighted in purple, is illustrated in this video:

Virtual morphologies generated with Deposit, the digital twins of real organic thin films, exhibit features commonly observed in (real) PVD generated organic layers such as anisotropic molecular orientation.

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Figure from: P. Friederich et al. ACS Appl. Mater. Interfaces 2018, 10, 1881−1887

We provide respective tools to analyze resulting giant surface potential (GSP) effects in thin films or anisotropic outcoupling in emission layers that are experimentally investigated e.g. using angular dependent emission spectroscopy.

Figure from: P. Friederich et al. Chem. Mater. 2017, 29, 9528-9535

Further, the electronic structure of morphologies can be analyzed with QuantumPatch to investigate spectroscopic material properties such as the material-specific DOS. 

Examples and details on the usage of the morphology generation tools: 

Scientific studies where these methods were applied:

  • T. Neumann et al., J. Comput. Chem., vol. 34 no. 31, 2013
  • P. Friederich et al., JCTC 2014 10 (9), 3720-3725
  • P. Friederich et al., Adv. Funct. Mater., vol. 26, no. 31, pp. 5757–5763, Aug. 2016
  • P. Friederich et al. ACS Appl. Mater. Interfaces 2018, 10, 1881−1887
  • P. Friederich et al. Chem. Mater. 2017, 29, 9528-9535
  • S. Bag, et al., Sci Rep 9, 12424 (2019)
  • F. Symalla et al., SID Symp. Dig. Tech. Pap., vol. 49, no. 1, pp. 340–342, 2018.
  • F. Symalla et al., Phys. Rev. Lett., vol. 117, no. 27, Dec. 2016
  • F. Symalla et al., SID Symp. Dig. of Tech. Pap., 50: 259-262, 2019